/*
 *  Copyright 2013 National Institute of Advanced Industrial Science and Technology
 *  
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.sss.util;

import java.util.Collections;
import java.util.Enumeration;
import java.util.Properties;
import java.util.Vector;

/**
 * <code>SortedProperties</code> is a kind of <code>Properties</code>
 * which support sorted output on the keys.
 */
@SuppressWarnings("serial")
public class SortedProperties extends Properties {
  /**
   * @return sorted keys.
   */
  @Override
  public Enumeration<Object> keys() {
    Enumeration<Object> keysEnum = super.keys();
    Vector<String> keyList = new Vector<String>();
    while (keysEnum.hasMoreElements()) {
      keyList.add((String) keysEnum.nextElement());
    }
    Collections.sort(keyList);
    Vector<Object> sortedKeyList = new Vector<Object>();
    for (Object keyString: keyList) {
      sortedKeyList.add(keyString);
    }
    return sortedKeyList.elements();
  }
}
